1Heat oven to 350°F. Line 8-inch square pan with foil; spray foil with cooking spray.
2In 3-quart saucepan, melt 1/2 cup chocolate chips and 1/2 cup butter over low heat, stirring constantly; remove from heat. Cool completely. Stir in brown sugar, eggs, 2 tablespoons liqueur and the vanilla with whisk. Stir in flour, cocoa and salt. Spread evenly in pan. Bake 20 minutes or until center is set. Cool completely.
3In medium bowl, beat frosting ingredients with electric mixer on medium speed until smooth and spreadable. Frost brownies. Refrigerate at least 15 minutes. In small microwavable bowl, microwave glaze ingredients on High 1 minute; stir. Microwave 15 seconds longer; stir until melted and smooth. Pour glaze over frosting; spread to cover. Refrigerate until set. With wet knife, cut into 8 rows by 4 rows. Store covered in refrigerator.